What exactly is the "five (consecutive) word" plagiarism rule?

My understanding is that the toughest standard regarding plagiarism is the "five (consecutive) word" rule, which holds that, if there are five consecutive words identical to someone else's writing, then you are guilty of plagiarism.

This does not apply to, say, proper names like "The Loyal Order of Freemasons", which is considered one word, not five, but what about proverbs or trite expressions such as "My country right or wrong"?

My further understanding is that there are also "looser" standards for determining plagiarism (for example, ten or twenty consecutive "copied" words). When do such standards apply, and when does the five word standard apply?

Answer

I haven't heard this five-word rule. But I can easily think of many sequences of five words that no one would seriously consider plagiarism.

I think that I will

was the first time that

Britain, France, Germany, and Italy

all men, women, and children

March 1 of this year

turn left at the traffic light (that's six!)

five words in a row

Etc etc.

If some university or whatever institution is classifying as "plagiarism" any use of five words in a row that have ever previously been used anywhere in the world, I think that every student there, not to mention every faculty member, is guilty of plagiarism.

You can't rationally define plagiarism simply in terms of the number of words that are the same. Many short strings of words like those above are the most simple and direct way of expressing a common idea. If you never heard one of those phrasings before, you'd be likely to invent it.

I'm reminded of a TV comedy I saw years ago where a writer of home repair books was accused of plagiarism. And so in court the other writer's lawyer read samples from the two books that were word-for-word identical. Statements like, "Attach the faucet using two screws." At one point the defendant says, "How many ways are there to say, 'Attach the faucet using two screws.' 'Put in the two screws to attach the faucet.' 'Screw in the faucet with two screws.' 'See the two screws? Put 'em in.'"

On the other hand I can think of many short phrases that surely would be plagiarism. Like, "I have nothing to offer but blood, toil, tears, and sweat." "The ultimate question of life, the universe, and everything." "In the beginning, God created the heavens and the earth." "I think, therefore I am." (That's only three words in the original Latin: "Cogito, ergo sum.") If you used one of those strings of words in a way that implied it was original, I think you would be guilty of plagiarism.